When I attach a picture to an email it's huge, taking up to 1 megabite. Is there some free software that will allow my pictures to be smaller so I can attach more?

If you have Photoshop, check out the "Save for Web..." item under the File menu. This feature lets you interactively tweak various parameters that affect the size and quality of the picture, while seeing what effect they will have.

If you really need/want to send the hi res picture or other big files, you can send files up to 100mb through a free service like www.yousendit.com

Try this: http://www.acumensystems.com/mir/default.aspx

"Multiple Image Resizer" -- resize a folder at a time.

or, you can upload photos to a service like flickr -- and link to your email -- flickr (http://www.flickr.com) does on the fly image resizing.

Your pictures are probably too big size-wise. You can use Microsoft Paint (should be on your computer already, check your Accessories folder or just run mspaint) to shrink them.
From the Image menu, choose Stretch/Skew, then stretch to, say 50% horizontal and vertical. See if that takes care of it.
Also, if the images are photographs, make sure you're saving them as JPEGs. Paint can do this, so be sure to select JPEG from the "Save as type" box when you save your shrunken picture.

In most versions of Windows you can right click on a picture from Windows Explorer (my computer). One of your options will be 'send in an email' - or some similar wording that means that. If you do this, you will be offered options for size. Choose small to shrink your picture to a lower resolution, smaller size.

THE SIMPLEST WAY would to be changing the file format to .jpeg instead of .bmp or other file names. Jpeg files are slightly lower quality but attach 10x faster

The best choice would be an image converter. One is already recommended in your existing answers. I use AZImage, see http://www.racsoftware.com/imageconverter.php . It has a trial period with no disabled features and allows for upload to Google Picasa and Facebook.

You can find one their page some linked video tutorials that may help you decide if the program will fit your usecase.